In what could signify a lucrative turning point for online activism, a viral campaign spreading throughout the U.K., Europe and Australia has reportedly raised millions of dollars for cancer-research organizations in just a few days.

The campaign #NoMakeupSelfie began in much the same way as any other viral trend: with a cause, a hook, and a catchy hashtag that spread like wildfire throughout the digital hinterlands of popular social networks. In this case, the campaign involves social media users -- mostly women -- posting photos of themselves wearing no makeup as a means of raising awareness for cancer research. The trend blew up on Facebook, Twitter and Instagram, where it met with almost immediate resistance by critics who saw it as yet another example of slacktivism -- an empty gesture in which social media denizens take an important issue and use it as another excuse for online attention-seeking.

But then something unusual happened. The organization Cancer Research UK seized the opportunity to ask those thousands of hashtag spreaders to put their money where their iPhones are. On its Google+ page Wednesday, the group posted an update that changed the dynamics -- and the economics -- of the campaign.

“Thousands of you are posting #cancerawareness #nomakeupselfie pictures and many have asked if the campaign is ours. It’s not but we love that people want to get involved! If you’d like to help #beatcancersooner, please visit our website at http://bit.ly/1fGSnmq or text to donate using the code in the picture.”

The selfie posters responded, and soon the group was being flooded with donations. The above link took visitors to the group’s “Text to Donate” page, which details more than a dozen donor plans. For instance, by texting “Stand” to 70007, supporters can donate as little as £3. At last count, Cancer Research had raised more than £2 million.

Other groups got in on the act as well. The Irish Cancer Society announced Friday that donations have doubled in the past 24 hours, from €200,000 to €400,000. The group credited the hashtag campaign and thanked participants for their “incredible generosity.” The group CoppaFeel, which seeks to prevent breast cancer by encouraging regular breast checks, said on Twitter that it raised almost £2,000. And the Australian Cancer Research Foundation, without mentioning specific amounts, posted an update Friday saying it has been “overwhelmed” by the support from the selfie-posters. “The power of social media is incredible,” the group wrote.

The campaign has sparked numerous blog posts and divisive media commentary about the value, or lack thereof, of clicktivism -- traditionally a pejorative term meant to characterize the largely symbolic and narcissistic nature of many displays of online solidarity. One day it’s a pink equal sign for gay rights; the next it’s a blue-and-yellow ribbon for protesters killed in Ukraine. While some argue that there is no harm in these simple demonstrations of support, critics contend such campaigns pose a threat to meaningful civic engagement. Why donate to your local charity when you’ve already posted three different selfies this week? And there is some evidence to back up that cynical view. A study of online activism released in February revealed that the 1.2 million-member “Save Darfur” Facebook campaign did little more than conjure the “illusion of activism rather than facilitating the real thing.”

Not so in the case of #NoMakeupSelfie. If the organizations on the receiving end are to be believed, those clicks are translating to real dollars. In that sense, the campaign is a kind of hybrid between online activism and crowdfunding, combining the spirit of Change.org with the payment model of Kickstarter. If you’re someone who believes the world can be changed one click at a time, that’s not a bad combination.

The #NoMakeupSelfie was still going strong as of late Friday afternoon, with tweets pouring in at more than 30 per minute.

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